Alloy steel and articles made therefrom



Patented Nov. 1 9, 1935 UNITED STATES.

PA-TENT OFFICE 2,021,782 ALLOY STEEL AND ARTICLES MAD THEREFROM trustee No Drawing. Application November 20, 1931, Serial No. 576,429

5 Claims.

Our invention relates to alloy steels which are required to withstand stresses of considerable magnitude at elevated temperatures that is above 750 F., which is resistant to oxidation at the properties of the steel at high temperatures. Preferably the tungsten content is substantially smaller in amount than the chromium, some.- times being as little as one-half the chromium such temperatures and which is considerably content. lower in cost than the austenitic steels or chro- Tests of numerous specimens of steel within mium steels, commonly used at such temperathe above range have shown such steels to be tures. resistant to oxidation at high temperatures, to

The principal object of our invention is an have ahigh proportional limit value at high temalloy steel suitable for use at such high temperaperatures, to have high creep resistance and tures but containing sufliciently small amounts load carrying ability t have a high degree of of alloying elements to make the cost of the steel strength, a suitable amount of ductility and good comparable tothat of simple alloy steels. resistance to shock. The steel has an excellent The invention consists principally in a combination of qualities at low or room temperachromium-tungsten-sllicon steel, with or witht r as well-as t high temperatures out vanadium, having substantially the followmg composition: Physzcal properties at 75 F.

Per cent Carbon 0.20 to 0.60 '1 i P 15' p y; Manganese 0.20 to 1.0 slwfgntsh f mi); '0 $321 32, .331 1 13" 811mm 0.50 to 1.0 i 2 he... PM Chromium 0.75 to 1.50 Tungsten 0.50 to 1.50 180.000-M5.000100,000-220,000 0. 518.0 8.0-54.0 270-480 20-55 Vanadium 0.01 to 0.50

. with the usua percentages of u p and p Composition. .39%C, .53%Mn, .68%S1, .84%W, 1.18%(1 phorus. The invention further consists in the T n P B alloy steel and articles made therefrom hereint m B ropqrtional Percent percent Izod after described and claimed. 521 53 1 11 Our alloy steel is suitable for such articles as valve parts used in high temperatures, oil lines, r mgh temperature steam lines. stay rods in stills 140,000-250,000105,000-200,000 1.5-15.0 10.5-40.0 210-445 9.5-62.5 and boilers, bolts for high temperature applications and castings and forglngs for valve bodies, composition: .4620, .47%Mn, .7Z%S1, .90%W, 1.35%(1, .30%V v and other similar articles. i/ il p ri es at 1,000 F.

It is recognized that chromium-tungsten-silicon steels have been used as tool steels in the T P 1 Creep manufacture of such tools as drills, taps, ream- 1013 1 1: l bs. ittiiitf J1??? 353 535, 15 g? ers and chisels; but such prior steels have not 100,800 hrs. been satisfactory for use in the articles herein 40 set forth or at high temperatures. 88,000.91 24'00HM00 7H3 The range of ingredients of our alloy steel is as follows: P t Composition: .:10%o, .53%Mn, .68%Si, .s4%w, 1.18%Cr er cen Carbon 0.20 to 0.60 Creep Mangan 020 to 1.0 ..mtifii'ibs. 537005? 33 g..- gg fgg gtg gg; Silk-rm v 0.50 to 1.0 Per 100,112 011. Chromium 0.75 to 1.50 5:2 :23;

A preferred narrower range of ingredients is: Composition: .46%C, .47lllln, .72%Si, .9U%VV, 1.35%01, .30',{;V

Per cent The qualities and characteristics of our alloy Carbon 050 to 050 steel as hereinbefore brought out make said steel "f highly desirable for the uses hereinbefore set Manganese 0.40 to 0.60 Simon 0 to 1 0 forth and in other articles requiring a low priced steel having a good combination of properties at Chromium 0.75 to 1.25 Tungsten to 1.0 hignllihtegnperaitures and also at low temperatures.

a we c mm is:

- 1. An article, such as a boiler tube or the like,

Vanadium in amounts from 0.01 to 0.50% may form at high temperatures the article being be used in said steel, the vanadium improving formed from a steel alloy characterized by maintained high creep strength under continuous exposure to operating stress at temperatures in excess of 750 F., by substantial resistance to oxidation at operating temperatures, and by containing from more than 0.2 to not more than about v tained high creep strength under continuous exposure to operating stress at temperatures in excess of 750 F., by substantial resistance to oxidation at operating temperatures, and by containing from about 0.4 to 0.5 per cent of carbon, about 0.75 to 1.25 per cent of chromium, about 0.4 to 0.6 per cent of manganese, about 0.6 to 1.0 per cent of silicon, about 0.75 to 1.0 per cent of tungsten, the tungsten content being less than the content of chromium, and the remainder of the steel being substantially iron.

3. An article, such as a boiler tube or the like, for use at high temperatures the article being formed from a. steel alloy characterized by maintained high creep strength under continuous exposure to operating stress at temperatures in ex-; cess of 750 F., by substantial resistance to oxidationat operating temperatures, and by containing more than 0.2 to not more than about 0.6 per cent of carbon, about 0.75 to less than about 1.5 per cent of chromium, about 0.2 to 1.0

per cent of manganese, about 0.5 to 0.9 per cent or silicon, about 0.5 to 1.5 per cent of tungsten. about 0.01 to 0.5 per cent of vanadium, the tungsten content being less than the content of chromium, and the remainder of the steel being 5 substantially iron.

4. An. article, such as a.- boiler tube or the like. for use at high temperatures the article being formed from a steel alloy characterized by maintained high creep strength under continuous ex- 10 posure to operating stress at temperatures in excess of 750 F., by substantial resistance to oxidation at operating temperatures, and by containing from about 0.4 to 0.5 per cent of carbori,

18.130110 0.75 to 1.25 per cent of chromium, about 15 0.4 to 0.6 per cent of manganese, about 0.6 to 1.0 per cent of silicon, about 0.75 to 1.0 per cent of tungsten, about 0.01 to 0.5 per' cent of vanadium. the tungsten content being less than the content of chromium, and the remainder of the steel be- 0 ing substantially iron.

5. An article for use at high temperatures the article being formed from a steelalloy characterized by maintained high creep strength under continuous exposure to operating stress at temg5 peratures in excess of 750 F., by substantial resistance to oxidation at operating temperatures, and by containing about 0.46 per cent or carbon, about 1.35 per cent of chromium, about 0.47 per cent of manganese, about 0.72 per cent of silicon, 30 about 0.9 per cent of tungsten, about 0.3 per cent of vanadium, and the remainder of the steel being substantially iron.

WALTER G. HILDORF.

ALBERT E. WHITE.

CLAUDE L. CLARK; 

